a. Field of the Invention
The present invention relates to a microscope objective and, more particularly, to a microscope objective of achromat class for which flatness of image is high.
b. Description of the Prior Art
For most of known microscope objectives of this kind, the image is flat only at the middle portion and is not satisfactorily flat toward the marginal portion. Besides, for known microscope objectives of this kind for which the image is flat for a comparatively wide range, the numerical aperture is small.